45 research outputs found
A Genome-Wide Association Study of Female Sexual Dysfunction
PMCID: PMC3324410. CCBurri LC et al.PLOS Genet Doi:10.1371/journal.pone.0035041Female sexual dysfunction (FSD) is an important but controversial problem with serious negative impact on women's quality of life. Data from twin studies have shown a genetic contribution to the development and maintenance of FSD
Support for maternal manipulation of developmental nutrition in a facultatively eusocial bee, Megalopta genalis (Halictidae)
Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish from other environmental factors. This is an important distinction within the context of social evolution, because if variation in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content, for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social plasticity observed in M. genalis
Ants Sow the Seeds of Global Diversification in Flowering Plants
Background: The extraordinary diversification of angiosperm plants in the Cretaceous and Tertiary periods has produced an
estimated 250,000β300,000 living angiosperm species and has fundamentally altered terrestrial ecosystems. Interactions
with animals as pollinators or seed dispersers have long been suspected as drivers of angiosperm diversification, yet
empirical examples remain sparse or inconclusive. Seed dispersal by ants (myrmecochory) may drive diversification as it can reduce extinction by providing selective advantages to plants and can increase speciation by enhancing geographical
isolation by extremely limited dispersal distances.
Methodology/Principal Findings: Using the most comprehensive sister-group comparison to date, we tested the hypothesis that myrmecochory leads to higher diversification rates in angiosperm plants. As predicted, diversification rates
were substantially higher in ant-dispersed plants than in their non-myrmecochorous relatives. Data from 101 angiosperm
lineages in 241 genera from all continents except Antarctica revealed that ant-dispersed lineages contained on average
more than twice as many species as did their non-myrmecochorous sister groups. Contrasts in species diversity between
sister groups demonstrated that diversification rates did not depend on seed dispersal mode in the sister group and were
higher in myrmecochorous lineages in most biogeographic regions.
Conclusions/Significance: Myrmecochory, which has evolved independently at least 100 times in angiosperms and is
estimated to be present in at least 77 families and 11 000 species, is a key evolutionary innovation and a globally important driver of plant diversity. Myrmecochory provides the best example to date for a consistent effect of any mutualism on largescale diversification
Ex Vivo Expansion of Human CD8+ T Cells Using Autologous CD4+ T Cell Help
Background: Using in vivo mouse models, the mechanisms of CD4+ T cell help have been intensively investigated. However, a mechanistic analysis of human CD4+ T cell help is largely lacking. Our goal was to elucidate the mechanisms of human CD4+ T cell help of CD8+ T cell proliferation using a novel in vitro model. Methods/Principal Findings: We developed a genetically engineered novel human cell-based artificial APC, aAPC/mOKT3, which expresses a membranous form of the anti-CD3 monoclonal antibody OKT3 as well as other immune accessory molecules. Without requiring the addition of allogeneic feeder cells, aAPC/mOKT3 enabled the expansion of both peripheral and tumor-infiltrating T cells, regardless of HLA-restriction. Stimulation with aAPC/mOKT3 did not expand Foxp3+ regulatory T cells, and expanded tumor infiltrating lymphocytes predominantly secreted Th1-type cytokines, interferon-Ξ³ and IL-2. In this aAPC-based system, the presence of autologous CD4+ T cells was associated with significantly improved CD8+ T cell expansion in vitro. The CD4+ T cell derived cytokines IL-2 and IL-21 were necessary but not sufficient for this effect. However, CD4+ T cell help of CD8+ T cell proliferation was partially recapitulated by both adding IL-2/IL-21 and by upregulation of IL-21 receptor on CD8+ T cells. Conclusions: We have developed an in vitro model that advances our understanding of the immunobiology of human CD4+ T cell help of CD8+ T cells. Our data suggests that human CD4+ T cell help can be leveraged to expand CD8+ T cells in vitro